The coupling of scattered-bend loss in POF based the displacement measurement sensor

In this paper, a displacement sensor is proposed based on the coupling of scattering loss during the bending of fiber. We adopted a twisted structure of two fiber to couple the scattered loss which caused by bending. Two polymer optical fiber were used in the experiment and the fibers were twisted and bent. When the fiber draft then the bent radius becomes shorter. The scattered-bend loss was arisen from illuminating fiber and being coupled in receiving fiber. The proposed sensor has range about 150 mm and the sensor used for static, dynamic and plane-in-out measurement. The sensor has good linearity between 0 mm to 80 mm, having the sensitivity of 1.26 nW \mm, resolution of 0.79 mm, and repeatability error of 1.26%. The design structure of the sensor is simple, holistic and cost-effective and has potential advantages on industrial application.